Studies on Influence of WC on Scratch and Hot Corrosion Resistance of AISI H13 Steel by Flame-Sprayed Coatings of EWAC 1001

K Gokul Kumar,N Arivazhagan

doi:10.5402/2011/273706

Abstract

This paper presents the experimental investigations carried out to study the influence of addition of Tungsten Carbide (WC) on the scratch resistance and high-temperature corrosion behaviour of flame-sprayed EWAC 1001 coatings on the AISI H13 steel substrate. The improvement in properties was analysed by conducting various tests such as microstructural analysis, microhardness, and scratch tests. Moreover, high-temperature corrosion tests were carried out on the coated as well as uncoated AISI H13 steel by exposing the material to air oxidation at 700°C under cyclic conditions. The thermogravimetric technique was used to establish kinetics of corrosion, whereas XRD and SEM/EDAX techniques which were used to analyze the AISI H13 steel with EWAC 1001 coating containing WC showed better resistance to high-temperature corrosion as compared to that of uncoated AISI H13 steel. It is observed that the formation of Cr2O3, NiO, and NiCr2O4 contributes to the enhancement of high temperature corrosion resistance of the coating. The formation of unprotective Fe2O3 oxide leads to intense spalling and peeling of the scales in the uncoated material. The results presented in this paper would be beneficial for improving properties of tools used in the die-casting industry.

Highlights

Molten aluminium corrosion is one of the major problems in the aluminium production industry since the molten aluminium reacts with most metals and metal oxides [1]
The effect of flame spray coating on high temperature corrosion in air oxidation environment at 700◦C has been studied
The cumulative properties of coated and uncoated AISI H13 steel are shown in Table 3 and the conclusions are as follows

Summary

Introduction

Molten aluminium corrosion is one of the major problems in the aluminium production industry since the molten aluminium reacts with most metals and metal oxides [1] These days the most frequently used die materials are hot work tool steels such as AISI H11 and AISI H13 grades [2]. It is widely known that EWAC 1006EE is a Co–Cr–W–Ni–C base surfacing alloy which can be deposited using lowcost flame-spraying method and is, of greater commercial importance for abrasive wear applications [15]. Despite the importance of this tool material, to the best of the author’s knowledge, the high temperature corrosion behavior of EWAC 1001-coated AISI H13 steel is not reported in the specialized literature. The scope of the present investigation is to explore the improvement of corrosion resistance of AISI H13 steels after EWAC 1001 coating by flame spray technique. The characterizations of the coatings and corrosion products have been done using the combined techniques of optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy/energy-dispersive analysis (SEM/EDAX)

Experimentation

Findings

Result and Discussion

Conclusion